Wireless data/power transfer solutions typically use near-field communications and high quality (Q) factor magnetically coupled coils (inductors) to maximize energy transfer. In this case because a power supply can render the overall solution too bulky a known concept reduces the area of the inductors, so that the coil responsible for Rx/Tx of the data path signals is physically placed inside the power coil. Two different frequencies are used for communication on the power path and the data path, respectively, where the power path uses the lower frequency and the power path signal can often be of a significantly higher magnitude as compared to the desired data signal. This coil arrangement combined with the relatively high signal amplitude of the power path signal causes the power path signal to significantly magnetically couple into the data signal in the data path.
It is desirable for the same wireless data/power transfer solution to operate at various center carrier frequencies by simple programming of the receiver front-end using a minimum circuit area. Different applications or customers may have different bands of operation that will be selected or programmed via an on-chip frequency synthesizer. As the carrier frequency of the data signal changes, such as to avoid interference or to provide faster data rates, the coil dimension is changed in the pre-design for that particular band of operation, and the magnitude of the coupled power path signal changes. For an increase in carrier frequency, the coil dimension is reduced, and the magnitude of coupling of the power path signal is reduced, while for a decrease in carrier frequency, the coil dimension is increased, and the magnitude of the coupling of the power path signal is increased. As the carrier frequency of the data communication path increases, the data throughput increases. However, more unwanted signals (blockers) need to be filtered out in order to detect the data signals with the desired signal to noise ratio (SNR).